Getting properly kitted for winter camping almost always requires a heavy pack, but this featherweight will help save ounces. Our cold-sleeping female tester raved about the Drift after enduring brutal weather on Kilimanjaro. “It was snowing, hailing, and 0°F at 15,000 feet, but I slept through it.” Vertical baffles keep down positioned on top of you (as opposed to falling to the sides, with horizontal chambers). Premium 850-fill goose DownTek and a feathery 15-denier nylon shell keep weight low, but designers didn’t skimp on features like an extra hood draft tube and internal pocket. The bag crunches to 7 by 16 inches, which is on par with some three-season bags. The DWR-treated shell and hydrophobic down repelled moisture well; our tester didn’t notice a cold spot when the bag was pressed against a soaked tent wall all night. Bummer: The full-length zipper is snaggy. And then there’s the cost.